Paediatric Haematology Flashcards
What is the life span of:
- neutrophils?
- platelets?
- red blood cells?
- neutrophils 6-8hrs
- platelets 10 days
- red cells 120 days
Where are the main sites and stages of haematopoesis in embryonic/foetal life?
- Mesoblastic stage → occurs in extra-embryonic structures e.g. yolk sac/placenta from 2-12/40
- Hepatic stage → predominant blood production site from 6-24/40, ↓ in 2nd trimester, 85% erythroid (no neutrophils)
- Myeloid stage from 24/40 onwards, 40% erythroid (15% neutrophils)
What happens to red cell, neutrophil, and platelet size/numbers during foetal life?
Red cells - higher MCV and MCH but lower Hb and Hct 22/40 - at term, MCV/MCH lower and Hb/Hct higher
Platelets - same size, but numbers gradually increase from 22/40
Neutrophils - none before 2nd trimester and scarce in blood until 3rd. Lots of progenitor cells in blood.
What is the Kleihauer-Betke test?
Acid elution test
Determines if fetal RBCs in maternal circulation
Describe the clinical phenotype of Fanconi anaemia:
- Abnormal thumbs, absent radii, short stature
- skin hyperpigmentation e.g. café au lait spots
- abnormal facial features (triangular face, microcephaly)
- abnormal development
- marrow failure
What is the main cancer that people with Fanconi anaemia get?
- AML
- Bone marrow failure 80% by age 20
Describe the clinical phenotype of Diamond-Blackfan anaemia:
- anaemic, pale neonate/infant (75% by 6/12)
- short stature with craniofacial abnormalities (e.g. cleft lip, hypertelorism, micrognathia), web neck
- triphalangeal thumb (classical)
- absent/abnormal kidney e.g. horseshoe (25% have abnormal phenotype)
What are the laboratory findings in Diamond-Blackfan anaemia:
- normochromic macrocytic anaemia
- low reticulocytes
- thrombocytosis (rare: thrombocytopenia)
- marrow normally cellular aside from RBC precursors
- diagnostically: erythrocyte adenosine deaminase (ADA) activity is increased
- generally RBCs only affected line
What cancers do you get with Diamond-Blackfan?
- acute myelogenous leukemia
- myelodysplastic syndrome
- female genital Ca
- osteosarcoma
What is activated protein C resistance associated with?
- Factor V Leiden mutation
- inability of protein C to cleave factor Va and VIIIa.
- longer duration of thrombin degradation, hypercoagulable state
What are the clotting pathways assessed by APTT?
- Intrinsic coagulation pathway (factors XII, XI, IX, VIII)
- Final common pathway (factors II, V, X and fibrinogen).
What areas is G6PD defect common in?
- Mediterranean region (esp Greece, Italy)
- Philippines
- China
- Africa
What are common triggers for G6PD?
- Fava beans
- nitrofurantoin
- co-trimoxazole
- primaquine
- chloraquine
What is the typical presentation of LCH?
- Presents with osteolytic bone lesions +/- multi-organ involvement
- LCH cells can infiltrate most body tissues (except kidney and heart)
Histiocyte markers CD1a, S100, and CD207
(langerin) makes you think…
Langerhans Cell Histiocytosis
Birbeck granule – a tennis racket shaped granule in the cytoplasm of cells on electron microscopy is associated with…
Langerhans Cell Histiocytosis
Presentation: Short with skeletal dysplasia, eczema, learning difficulties, poor feeding/FTT/steatorrhoea, may have increased infections (mild neutropenia +/- low Hb +/- low platelets)
Schwachman-Diamond Syndrome (exocrine pancreatic insufficiency, bone marrow dysfunction, skeletal abnormalities and short stature)
What is in cryoprecipitate?
- factor VIII
- fibrinogen
- vWF
- factor XIII
What is the most common cause of familial thrombophilia (deep vein thrombosis and pulmonary emboli)?
Activated protein C resistance/Factor V Leiden (white population)
Why might you get low haptoglobin?
- Intravascular Haemolysis
- Wilsons
(Haptoglobin: acute phase reactant, mops up free haemoglobin from outside RBCs to stop it being toxic)
What are the most important inhibitors of the coagulation cascade?
- Antithrombin
- Protein C
- Protein S
What are the different types of vW disease?
Type 1: low levels of vWF, most common ~70%
Type 2: change in vWF function, range of defects
Type 3: complete deficiency of vWF
What is the typical skeletal anomaly with Diamond-Blackfan?
- triphalangeal thumb
What is the typical skeletal anomaly with Fanconi anaemia?
- abnormal thumbs e.g extra/duplicate, absent, dangling
- absent radii
What is foetal haemoglobin (HbF) comprised of?
2 alpha chains and 2 gamma chains
What is HbA2 (the other adult haemoglobin) comprised of?
2 alpha chains and 2 delta chains
Which infective gastroenteritis is associated with iron malabsorption?
Giardia lamblia infection
What is the diagnostic test for hereditary spherocytosis?
EMA binding test
What class of antibody is warm antibody autoimmune haemolysis?
IgG
What class of antibody is cold antibody autoimmune haemolysis?
IgM, anti I/i
What is the most common drug causing autoimmune haemolysis?
Cephalosporins
The most common cause overall is probably post infectious (e.g. mycoplasma, EBV)
What cancer do you worry about with bone marrow failure syndromes?
AML for all of them
Fanconi anaemia & dyskeratosis congenita give you SCC
Diamond-Blackfan - sarcoma
What is the half-life of the vitamin K dependent factors?
VII - 4-6 hours IX - 24 hours X - 24-48 hours II - 60 hours Protein C - 8 hours Protein S - 30 hours
In what condition(s) do you see target cells on the blood film?
Thalassemias
In what condition(s) do you see spherocytes on the blood film?
Hereditary spherocytosis
Autoimmune haemolytic anaemia
What is the most likely coagulopathy? 4/12 male, significant oozing from wound following talipes repair. Breastfed, well, no PMH/FHx bleeding.
Hb 45 g/L [95-140], PT-INR 1.2 [1.0-1.4], APTT 120
Factor VIII deficiency/haemophilia A
What helps distinguish intra/extravascular haemolysis?
Urinary haemosiderin
Signs of intravascular haemolysis?
- low haptoglobin
- urinary haemosiderin/haemoglobin
- high LDH
